The AGC on these is RF AGC. Put on strong signal & adjust
till the pix goes snow then turn back until the snow JUST clears
up. Its touchy & will cause the jitters if set to high.
BTW for you & others. Zenith made a training manual with
paper & cassettes that covers the 4 tube hybrid, flat chassis &
the CC2 upright chassis. I recommend it, I see them on e-bay
now & then. Its amazing how close they are to each other & uses
many of the same parts & design. Great way to see slow evolution.
73 Zeno
LFOD !